The answer harkens back to the C roots of Objective-C. Objective-C was originally written as a compiler pre-processor for C. That is, Objective-C wasn’t compiled so much as it was transformed into straight C and then compiled. Start with the definition of the type id. It is declared as: typedef struct objc_object { Class isa; … Read more
There’s at least 1 known bug in Apple’s upload server that they’ve not fixed for more than 12 months. Things to beware of: Apple deletes any leading zeroes inside the version number; i.e. the “whole string” is NOT treated as a number, instead the bits between dots are treated as SEPARATE numbers. e.g. “1.02” is … Read more
Try one of the following, depending on your image format: UIImageJPEGRepresentation Returns the data for the specified image in JPEG format. NSData * UIImageJPEGRepresentation ( UIImage *image, CGFloat compressionQuality ); UIImagePNGRepresentation Returns the data for the specified image in PNG format NSData * UIImagePNGRepresentation ( UIImage *image ); Here the docs. EDIT: if you want … Read more
Before you implement any exotic hacks to get around this problem, try this: stop the debug session, close the app from multitasking, unplug your device from the computer and run the app normally by tapping its icon. I have seen at least two cases in which the delay only occurs while the device is plugged … Read more
You can convert an NSString into a double with double myDouble = [myString doubleValue]; Rounding to the nearest int can then be done as int myInt = (int)(myDouble + (myDouble>0 ? 0.5 : -0.5)) I’m honestly not sure if there’s a more streamlined way to convert back into a string than NSString* myNewString = [NSString … Read more
The answer is… well… simple. Simplicity and consistency, in fact. Objective-C is purely dynamic at the moment of method dispatch. In particular, every method dispatch goes through the exact same dynamic method resolution point as every other method dispatch. At runtime, every method implementation has the exact same exposure and all of the APIs provided … Read more
By default, when you create a new iOS project in Xcode 4.5, your storyboard or XIB is set to use Autolayout, which is a new feature in iOS 6.0. The NSLayoutConstraint class is part of the Autolayout system, and it doesn’t exist in older versions of iOS. If you want to deploy your app to … Read more
You should create a UIView subclass for your top view and override the following method: – (BOOL)pointInside:(CGPoint)point withEvent:(UIEvent *)event { // UIView will be “transparent” for touch events if we return NO return (point.y < MIDDLE_Y1 || point.y > MIDDLE_Y2); } You may also look at the hitTest:event: method.
I’m pretty sure this is just a bug in iOS 8.0. It’s reproducible with the simplest of POC apps that does nothing more than attempt to present a UIImagePickerController like you’re doing above. Furthermore, there’s no alternative pattern to displaying the image picker/camera, to my knowledge. You can even download Apple’s Using UIImagePickerController sample app, … Read more
If I decide to upgrade to iOS 5, do I need to remove all [myObject retain] and [myObject release] statements from my code? Yes, but XCode 4.2 includes a new “Migrate to Objective-C ARC” tool (in the Edit->Refactor menu), which does that for you. Calling dealloc is a different story. As mentioned in the comments … Read more